Elwha Watershed Information Resource

Upper Elwha watershed, in Olympic National Park. Robert Lundahl, National Park Service

An ecosystem can be described as a dynamic interaction between living (for example, plants, animals, and microorganisms) and non-living (for example, water, soil, and light) components that are influenced by human (anthropogenic) factors. Due to the construction of the Elwha River dams, the Elwha River ecosystem has been physically altered for over 90 years. During that time, the ecosystem has become degraded, and dam removal was identified as the best option for restoring fish runs and the Elwha River ecosystem.

The Elwha River watershed is composed of aquatic, terrestrial, riparian, and wetland ecosystems:

• Aquatic ecosystems encompass freshwater (such as rivers), estuary (areas where fresh and saltwater mix), nearshore (area from the treeline to average low water tide level), and marine (saltwater areas) environments. Water is the foundation of the aquatic food web that supports fish, amphibians, invertebrates, and other organisms.
• Terrestrial ecosystems (including forests and grasslands) are important to wildlife--especially the Elwha’s federally-listed threatened species such as the northern spotted owl (Strix occidentalis caurina), marbled murrelet (Brachyramphus marmoratus), and bald eagle (Haliaeetus leucocephalus).
• Riparian and wetland ecosystems are transition zones between aquatic and terrestrial areas. Riparian and wetland areas provide shoreline stability; reduce downstream flooding; improve water quality (by filtering sediments and chemicals); and provide nesting, feeding, and breeding habitat for wildlife.

Learn more about these habitats and research studies by clicking on the links below:

Aquatic: Research on primary and secondary producers, nutrients, and fish populations.

Riparian: Research on river floodplain, sediments, and conifer succession.

Terrestrial: Research on black bears, small mammals, and birds.

Nearshore: Research on sediment structure, habitat, and fish populations.

Wetlands: Research on water quality, nutrients, fish, amphibians, mammals, birds, and macroinvertebrates.